Images: Small Plane Crashes Near Golf Course

"I was on the tee box ... and it came straight at me and just off to the right side, maybe about 10 feet above my head," said Robert Bartolomucci of Santee.

One of San Diego Fire Rescue's helicopters was at the nearby airport at the time and flew over to the golf course, where it picked up the two most-seriously injured young victims and flew them to Rady's Children's Hospital. The other child was taken to the same medical center by ambulance, and the man piloting the aircraft was taken to Sharp Hospital. All of the victims are in critical condition, said Maurice Luque of San Diego Fire Rescue. The children are all between the ages of 7 and 10 years old.

The pilot faced considerable obstacles trying to land the plane in the area, including water hazards and rugged, hilly terrain.

"Looked like he missed that electric pole there, and the wing hit the ground on the left side and just flipped him over," Bartolomucci said. "That was it."

The single-engine aircraft was home-built, according to Federal Aviation Administration officials. The plane took off from Montgomery Field at 12:45 p.m. and was headed to Fullerton, Calif. Authorities said the pilot radio'd the control tower shortly after takeoff that the aircraft had an open door and that the pilot was going to attempt to return to the airport for an emergency landing. FAA officials said the tower then lost radio contact with the aircraft.

The door was subsequently discovered in the 3400 block of Santo Road in Tierrasanta.

The FAA and the National Transportation Safety Board will investigate the crash, authorities said. It can take months for officials in such cases to identify the cause of such a crash.